The most important and most common substance on our planet, of course, is water. What can be compared with her in importance? It is known that life on Earth became possible only with the advent of liquid. What is water (hydrogen oxide) from a chemical point of view? What does it consist of and what properties does it have? Let's try to understand this article.
Hydrogen and its compounds
The lightest atom in the entire periodic system is hydrogen. It occupies a dual position, being located both in the halogen subgroup and in the first group of alkali metals. What explains these features? The electronic structure of the shell of his atom. He has only one electron that can freely both leave and attach another one to himself, forming a pair and completing the external level.
That is why the main and only oxidation states of this element are +1 and -1. It easily interacts with metals, forming hydrides - solid, non-volatile, salt-like compounds of white color.
However, hydrogen also readily forms volatile molecules of substances, interacting with non-metals. For instance:
- hydrogen sulfide H 2 S;
- methane CH 4 ;
- silane SiH 4 and others.
In general, hydrogen forms quite a lot of compounds. However, the most important substance in which it is composed is hydrogen oxide, the formula of which is H 2 O. This is the most famous compound that even a primary school student, not yet familiar with chemistry, recognizes by the formula. After all, water (and this is the highest hydrogen oxide ) is not only a common substance, but also a source of life on our planet.
The name of the element itself reflects its main essence - hydrogen, that is, "giving birth to water." Like any other oxide, this is also a binary compound with a number of physical, chemical properties. In addition, there are special characteristics that distinguish water from all other compounds.
An important class of compounds that hydrogen forms is acids, both organic and mineral.
Chemical properties of hydrogen
From the point of view of chemical activity, hydrogen is a rather strong reducing agent. In many reactions, it exhibits just such properties. However, when interacting with even stronger metals, it becomes an oxidizing agent.
Very important in industry is the interaction of hydrogen with metal oxides. After all, this is one of the ways to obtain the latter in pure form. Hydrogenotherm is a metallurgical method for the synthesis of pure metals from their oxides by reduction with hydrogen.
The reaction of hydrogen with oxide has the following general form: Me x O y + H 2 = H 2 O + Me.
Of course, this is far from the only way to synthesize pure metals. There are others. However, the reduction of oxides with hydrogen is an energetically rather profitable and uncomplicated production process, which has found wide application.
Also interesting is the feature that, when mixed with air, hydrogen gas can form a highly explosive mixture. Its name is explosive gas. For this, mixing should be carried out at the rate of two volumes of hydrogen per oxygen.
Water - Hydrogen Oxide
The fact that this oxide is very important, we have already mentioned several times. Now let's characterize it in terms of chemistry. Does this compound really belong to this class of inorganic substances?
To do this, try to write a slightly different formula: H 2 O = HOH. The essence is the same, the number of atoms is the same, however, now it is obvious that we have hydroxide. What properties should he have? Consider the dissociation of the compound:
HOH = H + + OH - .
Therefore, the properties are acidic, since hydrogen cations are present in the solution. In addition, they cannot be basic, because alkali forms only metals.
Therefore, another name that has hydrogen oxide is oxygen-containing acid of the simplest composition. Since such complex weaves are characteristic of a given molecule, therefore, its properties will be special. And the properties are repelled by the structure of the molecule, so we will analyze it.
Water molecule structure
For the first time, Niels Bohr thought of this model, and he belongs to the primacy and authorship in this matter. He established the following features.
- The water molecule is a dipole, since the elements included in its composition are very different in value of electronegativity.
- Its shape is triangular, at the base - hydrogens, and at the top - oxygen.
- Due to this structure, this substance is able to form hydrogen bonds, both between molecules of the same name, and with other compounds that have a strongly electronegative element in their composition.
You can see how the considered hydrogen oxide schematically looks in the photo below.
Physical properties of hydrogen oxide
Several basic characteristics can be identified.
- Physical state: gaseous - steam, liquid, solid - snow, ice.
- Boiling point - 100 0 (99.974).
- Melting point - 0 0 C.
- Water is able to shrink when heated in the temperature range from 0-4 0 C. This explains the formation of ice on the surface, which has a lower density and life preservation under the thickness of hydrogen oxide.
- High heat capacity, but very low thermal conductivity.
- In the liquid state of hydrogen, the oxide exhibits viscosity.
- A special property is surface tension and the formation of negative electric potential on the surface of the water.
As we noted above, the features of the properties depend on the structure. So it is here. The ability to form hydrogen bonds has led to similar features of this compound.
Hydrogen oxide: chemical properties
From the point of view of chemistry, the activity of water is quite high. Especially when it comes to reactions accompanied by heating. What is hydrogen oxide capable of reacting with?
- With metals that are in a series of voltages up to hydrogen. Moreover, with the most active (up to aluminum) special conditions are not needed, and those with lower reducing ability react only with steam. Those that stand after hydrogen are generally not able to enter into such interactions.
- With non-metals. Not with everyone, but with the majority. For example, in a fluorine atmosphere, water burns with a violet flame. Also, a reaction is possible with chlorine, carbon, silicon and other atoms.
- With metal oxides (basic) and acid (non-metals). Alkalis and acids are formed, respectively. Among metals, representatives of the first two groups of the main subgroups are capable of such reactions, except for magnesium and beryllium. Non-metals forming acid oxides interact with water all. An exception is river sand - SiO 2 .
The equation of the reactions of hydrogen oxide as an example is the following: SO 3 + H 2 O = H 2 SO 4.
Spread in nature
We have already found out that this substance is the most common in the world. Denote the percentage in the objects.
- About 70% of the body weight of humans and mammals. Some representatives of the fauna are composed of approximately 98% hydrogen oxide (jellyfish).
- 71% of the earth is covered by water.
- The largest mass is the waters of the oceans.
- About 2% is found in glaciers.
- 0.63% concentrated underground.
- 0.001% falls on the atmosphere (fog).
- The body of plants consists of 50% water, some species even more.
- Many compounds are found in the form of crystalline hydrates containing bound water.
This list can be continued for a long time, because it is difficult to recall at least something that does not include water or was not once included. Or formed without the participation of this oxide.
Production methods
The production of hydrogen oxide is not of industrial importance. It’s easier to use ready-made sources - rivers, lakes and other bodies of water than to spend a huge amount of energy and reagents. Therefore, in the laboratory, it is only appropriate to obtain distilled, especially pure water.
For these purposes, certain apparatuses are used, such as distillation cubes. Such water is necessary for many chemical interactions, since untreated contains a large number of impurities, salts, and ions.
Biological role
To say that water is used everywhere, to say nothing. It is inconceivable to imagine your life without this connection. From morning to night, a person constantly uses it for both domestic and industrial purposes.
The properties of hydrogen oxide imply its use as a universal solvent. And not only in the laboratory. But also in living beings, where thousands of biochemical reactions occur every second.
Also, water itself is a participant in many syntheses, it also serves as a by-product resulting from them. Over 60 years, every person on Earth passes about 50 tons of this amazing substance through himself!
Hydrogen oxide is used:
- in all industries;
- medicine;
- chemical syntheses;
- in all types of industries;
- domestic needs;
- agriculture.
It is difficult to determine the area of life in which you can do without water. The only living creatures that do not have hydrogen oxide in their composition and live without it are viruses. That is why it is difficult for a person to fight these organisms.